Biomedical subjects

K R Westerterp

Publications and source records attributed to K R Westerterp.

At least 145 records · Page 8Linked to original sources

PubMed1993

Habitual pattern of food intake in patients with liver disease.

Patients with liver disease are frequently undernourished. We determined the habitual pattern of energy intake and intake of protein, fat, carbohydrate and alcohol in patients with liver disease. 20 Patients differing with respect to cause, duration and severity of liver disease reported their habitual food intake using a 7-day food record. Control subjects formed a representative sample of the Dutch population. The results showed that patients with liver disease, had a significantly decreased daily energy intake (both expressed in absolute values and per kg body mass), compared with control subjects. Total fat intake was reduced in patients, whereas total intake of protein, carbohydrate and alcohol was similar to the control group. In the first 4 hours after rising, energy and protein intake were significantly increased in the patient group. During the evening the consumption of protein was lower in patients with liver disease than in control subjects. These findings are probably functional in order to minimize episodes of catabolism.

Journal Article↗

PubMed1993

Effect of the pattern of food intake on human energy metabolism.

The pattern of food intake can affect the regulation of body weight and lipogenesis. We studied the effect of meal frequency on human energy expenditure (EE) and its components. During 1 week ten male adults (age 25-61 years, body mass index 20.7-30.4 kg/m2) were fed to energy balance at two meals/d (gorging pattern) and during another week at seven meals/d (nibbling pattern). For the first 6 d of each week the food was provided at home, followed by a 36 h stay in a respiration chamber. O2 consumption and CO2 production (and hence EE) were calculated over 24 h. EE in free-living conditions was measured over the 2 weeks with doubly-labelled water (average daily metabolic rate, ADMR). The three major components of ADMR are basal metabolic rate (BMR), diet-induced thermogenesis (DIT) and EE for physical activity (ACT). There was no significant effect of meal frequency on 24 h EE or ADMR. Furthermore, BMR and ACT did not differ between the two patterns. DIT was significantly elevated in the gorging pattern, but this effect was neutralized by correction for the relevant time interval. With the method used for determination of DIT no significant effect of meal frequency on the contribution of DIT to ADMR could be demonstrated.

Adult↗

PubMed1993

Food quotient, respiratory quotient, and energy balance.

This paper reviews evidence that the macro-nutrient composition of the diet and the maintenance of energy balance are correlated. Intervention studies show that subjects lose weight on low-fat diets and gain weight on high-fat diets. Descriptive studies show that overweight subjects eat relatively more fat but have the same total energy intake as nonoverweight subjects. The body has a limited ability to oxidize fat compared with its ability to oxidize carbohydrate and protein. The conclusion is that becoming overweight can be prevented by reducing the fat content of the diet. Studies on nutrient utilization show a ready increase in carbohydrate oxidation whereas fat oxidation does not change after meals enriched with, respectively, carbohydrate or fat. However, in the long term, the respiratory quotient (RQ) is closer to the food quotient (FQ) for subjects eating high-fat diets than it is for subjects eating high-carbohydrate diets. For high-carbohydrate diets, the RQ is lower than is the FQ, indicating that subjects must mobilize body fat. This is supported by data on body weight loss in subjects changing from a standard maintenance diet to a low-fat diet, even while energy intake was increased with nearly 20%. Direct evidence for a higher energy expenditure for low-fat diets is not yet available.

Diet↗

PubMed1993

Frequency of feeding, weight reduction and energy metabolism.

A study was conducted to investigate the effect of feeding frequency on the rate and composition of weight loss and 24 h energy metabolism in moderately obese women on a 1000 kcal/day diet. During four consecutive weeks fourteen female adults (age 20-58 years, BMI 25.4-34.9 kg/m2) restricted their food intake to 1000 kcal/day. Seven subjects consumed the diet in two meals daily (gorging pattern), the others consumed the diet in three to five meals (nibbling pattern). Body mass and body composition, obtained by deuterium dilution, were measured at the start of the experiment and after two and four weeks of dieting. Sleeping metabolic rate (SMR) was measured at the same time intervals using a respiration chamber. At the end of the experiment 24 h energy expenditure (24 h EE) and diet-induced thermogenesis (DIT) were assessed by a 36 h stay in the respiration chamber. There was no significant effect of the feeding frequency on the rate of weight loss, fat mass loss or fat-free mass loss. Furthermore, fat mass and fat-free mass contributed equally to weight loss in subjects on both gorging and nibbling diet. Feeding frequency had no significant effect on SMR after two or four weeks of dieting. The decrease in SMR after four weeks was significantly greater in subjects on the nibbling diet. 24 h EE and DIT were not significantly different between the two feeding regimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Estimation of energy intake to feed subjects at energy balance as verified with doubly labelled water: a study in the elderly.

A study was intended to estimate energy intake (EI) for a nutrition intervention study. Subjects were 17 elderly men (age: 72 +/- 5 years) and 11 elderly women (age: 67 +/- 4 years). Two methods were used to measure EI: a 4-day dietary record (DR group; n = 12) or a dietary questionnaire (DQ group; n = 16). Subjects were fed for 3 weeks according to this intake during an intervention period, and energy expenditure (EE) was measured with doubly labelled water to verify the resulting figure for EI. Body weight and body composition were measured at the beginning of the second week and at the end of the third week, and metabolizable energy (ME) was calculated as gross energy intake (GEI) minus energy in faeces and urine. GEI, ME and EE did not differ between the DR and DQ groups (mean +/- SD for GEI: 10.09 +/- 1.21 and 9.29 +/- 1.36; ME: 9.09 +/- 1.28 and 8.34 +/- 1.31; EE: 10.13 +/- 1.57 and 9.25 +/- 0.35 MJ/d). In both groups ME was significantly lower than EE (DR group P < 0.05; DQ group P < 0.01). Body weight decreased significantly during the intervention period (mean +/- SD for DR group: -0.64 +/- 0.50 kg, P < 0.001; DQ group: -0.86 +/- 0.90 kg, P < 0.01). The change in body weight was significantly correlated with energy balance (ME - EE; P < 0.05). As shown from the results of the body composition measurements, body weight loss was a decrease of fat mass.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

Physical activity and energy expenditure in lean and obese adult human subjects.

We compared the physical activity of 11 lean and 11 obese men and women over a 7-day period. There were no significant differences in either the amount of movement recorded with an accelerometer (9.5 (SD 3.9) vs 9.9 (SD 2.6) kcounts.day-1), or in the energy expenditure due to physical activity reflected by the difference between the average daily metabolic rate measured by the doubly labelled water technique and the sleeping metabolic rate measured in a respiration chamber and adjusted for fat-free mass: 112 (SD 33) vs 118 (SD 22) kJ.kg-1.day-1. The obese showed a non-significant loss of body mass of 0.5 (SD 1.1) kg, probably due to reduced intake during the 7-day intake recording period.

Adult↗

PubMed1992

Comparison of heart rate monitoring combined with indirect calorimetry and the doubly labelled water (2H2(18)O) method for the measurement of energy expenditure in children.

The aim of the present study was to compare data on 24-h energy expenditure (EE24h) in nine boys and ten girls (mean age 9.3 and 8.1 years, respectively) by heart rates (fc) combined with energy expenditure obtained from a 1-day stay in an indirect calorimeter (EEcal) and a 2-week period of normal living using the doubly labelled water method (EEdlw). Individual calibration curves were derived from fc and oxygen uptake measured during sleep (in the calorimeter), standing and walking on a treadmill. An estimation of energy expenditure based on 24-h fc monitoring (EEfc) was made during the stay in the calorimeter and on a normal school-day. Mean results showed an overestimation in EEfc compared to EEcal and EEdlw of 10.4% and 12.3% respectively, varying from 6.3% to 16.2%. These results confirmed earlier observations in adults that for a group the fc method overestimates EE24h by about 10%.

Calorimetry, Indirect↗

PubMed1992

Fat-free mass as a function of fat mass and habitual activity level.

The best predictor of energy expenditure in man is the fat-free mass of the body. Fat-free mass explains most of the variation in resting metabolic rate and even in total metabolic rate under sedentary conditions. We studied possible determinants of fat-free mass as routes to influence energy metabolism. Existing data sets were analysed with observations on height, fat mass (FM), fat-free mass (FFM), and habitual level of physical activity (PA). PA was calculated from average daily metabolic rate (ADMR) as measured over 1-4-week intervals with 2H2(18)O and basal metabolic rate (BMR): PA = ADMR/BMR. Ninety-six subjects, 66 females and 30 males, from 7 different studies were included. FFM and FM were adjusted for height by taking its ratio to the square of height, in analogy with the body mass index. Subsequently, all analyses were corrected for origin of the data. In a regression analysis FM explained 53 and 40% of the variation in FFM in females and males, respectively. Adding PA to the model raised the explained variation in FFM in females to 62%. In contrast with females (r = 0.10, n.s.), there was an independent relationship between PA and FM in males (r = -0.41, p less than or equal to 0.05), such that a higher PA was related to a lower FM. In conclusion, FFM is a function of FM and PA. The absence of an effect of exercise training on FFM, i.e. additional exercise in weight-reduction programmes, is discussed.

Adipose Tissue↗

PubMed1992

Long-term effect of physical activity on energy balance and body composition.

We studied the effect of an increase in physical activity on energy balance and body composition without interfering with energy intake (EI). Sixteen women and sixteen men, aged 28-41 years, body mass index 19.4-26.4 kg/m2, not participating in any sport before the start of the experiment, prepared to run a half-marathon competition after 44 weeks. Measurements of body composition, EI and energy expenditure (EE) were performed before (0 weeks), and 8, 20, and 40 weeks after the start of training. Body composition was measured with hydrodensitometry and isotope dilution, and EI with a 7 d dietary record. EE was measured overnight in a respiration chamber (sleeping metabolic rate (SMR)) and in a number of subjects over 2-week intervals with doubly-labelled water (average daily metabolic rate (ADMR)). ADMR showed an average increase of 30% in both sexes from the start of training onwards while SMR tended to decrease. EI showed a tendency to drop from week 20 to week 40 in the men and a tendency to increase from week 20 to week 40 in the women. Body mass (BM) did not change in both sexes until the observation at 40 weeks when the median value of the change in men was -1.0 kg (P < 0.01; Wilcoxon signed-rank) while the corresponding change of -0.9 kg in the women was not statistically significant. Body composition changes were most pronounced in men as well. Based on changes in BM, body volume and total body water, men lost 3.8 kg fat mass (FM) (P < 0.001; Wilcoxon signed-rank) and gained 1.6 kg protein mass (P < 0.01; Wilcoxon signed-rank) while the corresponding changes in women were 2.0 kg (P < 0.05; Wilcoxon signed-rank) and 1.2 kg (P < 0.05; Wilcoxon signed-rank). In men the loss of FM was positively correlated with the initial percentage body fat (Pearson r 0.92, P < 0.001). In conclusion, body fat can be reduced by physical activity although women tend to compensate for the increased EE with an increased EI, resulting in a smaller effect on BM and FM compared with men.

Adult↗

PubMed1992

Sleeping metabolic rate in relation to body composition and the menstrual cycle.

The relationship between sleeping metabolic rate (SMR) measured from 0300 to 0600 h in a respiration chamber and body composition was studied in 47 healthy adult subjects (23 men and 24 women). The effect of the menstrual cycle on SMR was examined in 16 of the 24 women. SMR increased in the postovulation phase of the menstrual cycle (estimated as days 18-29 after last menstruation) 7.7% on average (P less than 0.001). A stepwise regression showed that both fat-free mass (FFM), fat mass (FM), and the phase of the menstrual cycle contributed significantly to SMR. After adjustment for FFM and FM, no sex differences in SMR (men vs preovulation women) remained. The inclusion of FM in this model is an improvement that eliminates the sex difference in SMR/FFM that is usually found. A prediction equation is given that explains 85% of the variance in SMR among individuals.

Basal Metabolism↗

PubMed1992

Total energy expenditure and spontaneous activity in relation to training in obese boys.

Obese boys [n = 10, aged 10-11 y, average percent body fat (%BF) 32.4] were given a regimented training program (4 wk, 5 1-h sessions, 45 min cycling/wk at 50-60% of predetermined VO2max) to investigate whether they modify their energy expenditure by reducing or augmenting their spontaneous physical activities. No change was observed in mean weight (52.7 vs 52.9 kg), %BF based on 2H- and 18O-dilution and densitometry (32.4 vs 31.7), sleeping metabolic rate (5.83 vs 5.68 MJ/24 h), and spontaneous activity by heart rate recording (percent time of light intensity: 85.3 vs 83.6; medium: 11.2 vs 12.4; and heavy: 3.5 vs 3.9) and activity questionnaires (861 vs 821 min physical activity/wk). There was a 12% increase in average daily metabolic rate by doubly labeled water, half of which can be explained by the energy cost of training and the rest by an increase in energy expenditure outside the training hour. In conclusion, training leads to an appreciable augmentation in the overall energy expenditure of obese children, even with a lack of change in spontaneous physical activity.

Adipose Tissue↗

PubMed1992

Energy expenditure climbing Mt. Everest.

Weight loss is a well-known phenomenon at high altitude. It is not clear whether the negative energy balance is due to anorexia only or an increased energy expenditure as well. The objective of this study was to gain insight into this matter by measuring simultaneously energy intake, energy expenditure, and body composition during an expedition to Mt. Everest. Subjects were two women and three men between 31 and 42 yr of age. Two subjects were observed during preparation at high altitude, including a 4-day stay in the Alps (4,260 m), and subsequently during four daytime stays in a hypobaric chamber (5,600-7,000 m). Observations at high altitude on Mt. Everest covered a 7- to 10-day interval just before the summit was reached in three subjects and included the summit (8,872 m) in a fourth. Energy intake (EI) was measured with a dietary record, average daily metabolic rate (ADMR) with doubly labeled water, and resting metabolic rate (RMR) with respiratory gas analysis. Body composition was measured before and after the interval from body mass, skinfold thickness, and total body water. Subjects were in negative energy balance (-5.7 +/- 1.9 MJ/day) in both situations, during the preparation in the Alps and on Mt. Everest. The loss of fat mass over the observation intervals was 1.4 +/- 0.7 kg, on average two-thirds of the weight loss (2.2 +/- 1.5 kg), and was significantly correlated with the energy deficit (r = 0.84, P < 0.05). EI on Mt. Everest was 9-13% lower than during the preparation in the Alps.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Changes in fat-free mass in obese subjects after weight loss: a comparison of body composition measures.

Estimates of body composition by densitometry were made in 84 apparently healthy subjects (42 men, 42 women) with a mean age of 40 +/- 6 years (mean +/- s.d.), before and after weight loss. The initial body mass index (BMI) was 30.7 +/- 2.3 kg/m2 and the achieved weight loss on a 4.2 MJ/day energy deficit diet for 13 weeks was 12.2 +/- 3.7 kg. The results by densitometry were compared with estimates obtained by four other techniques: deuterium oxide dilution, skinfold thickness, bioelectrical impedance (three equations) and BMI (two equations). The fat-free mass (FFM) loss estimated by densitometry in men and women was 2.8 +/- 1.8 kg and 1.3 +/- 1.3 kg respectively. The dilution technique gave comparable results with densitometry. The losses of FFM assessed by skinfold thicknesses, BMI and impedance equations were almost similar, but significantly larger than the reduction in FFM measured by densitometry. These deviations were mainly the result of significantly larger differences from densitometry before compared to after weight loss. No correlation was found between change in FFM by densitometry and change in resistance measured by the bioelectrical impedance method in both sexes. It is concluded that application of published prediction formulae in weight loss studies are less appropriate and will lead to changes in FFM that are significantly different from the changes estimated by densitometry or deuterium oxide dilution.

Adult↗

PubMed1991

The effect of a 5-month endurance-training programme on physical activity: evidence for a sex-difference in the metabolic response to exercise.

The effect of a 5-month endurance training programme on physical activity and average daily metabolic rate (ADMR) was studied. Subjects were 16 males and 16 females preparing for a half marathon. Total physical activity, measured using an accelerometer, had increased by 62% and 63% after 20 weeks in males and females, respectively. Physical activity during the non-exercise part of the day did not change although in males it tended to increase (15%, NS). The ADMR had increased significantly in males after 8 and 20 weeks (+2.3 and +3.3 MJ.day-1, respectively, P less than 0.05) and exceeded the net energy expenditure for endurance-training three to four times. In females no significant increase in ADMR was found (+1.5 and +1.3 MJ.day-1, after 8 and 20 weeks, respectively). In females the change in ADMR could be largely attributed to the net cost of running itself and a small increase (10%) in resting metabolic rate during the time of day they were awake. In males a discrepancy was observed between the increase of ADMR and the expenditure due to exercise and non-exercise activities. We suggest exercise stimulates habitual physical activity and diet-induced thermogenesis in males but not in females.

Adult↗

PubMed1991

Body composition and sleeping metabolic rate in response to a 5-month endurance-training programme in adults.

This study examined the effect of exercise training on body composition and sleeping metabolic rate (SMR) in 15 men and 13 women who participated in a 20-week training programme aimed at running a half marathon. Body mass (BM) was measured after waking up, fasted and with an empty bladder. Body composition was assessed using densitometry. The SMR was measured from 0300-0600 hours during an overnight sleep in a respiration chamber. Assessment of SMR was at least 36 h after the last period of exercise training. After 20 weeks of endurance training no change in BM was observed. However, body composition changed significantly. On average men lost 2.4 kg body fat (P less than 0.01) and gained 1.7 kg fat free mass (FFM) (P less than 0.01). In women fat loss averaged 0.9 kg after 20 weeks (P less than 0.01), while FFM increased by 1.0 kg (P less than 0.05). Loss of fat mass was significantly larger in males (P less than 0.05). No changes in SMR were found, either in absolute terms, or when normalised for BM or FFM. Therefore, we have concluded that exercise training has no chronic, long-term effect on SMR. A possible explanation for this outcome in view of the different findings in similar studies is discussed.

Adult↗

PubMed1991

Limits of energy turnover in relation to physical performance, achievement of energy balance on a daily basis.

Limits of energy turnover in relation to physical performance were addressed in terms of upper and lower limit, changes during a training programme and how to regulate energy balance at a changing energy turnover. At the lower limit we stress the risk of energy restriction to reach a desired body size or body composition for reduced performance, early osteoporosis and weight cycling. The upper limit of energy turnover can be increased by the consumption of energy dense carbohydrate-rich foods. Training induces an increase in energy turnover which can initially be more then twice the calculated energy costs from laboratory measurements of physical activity. In the long term, training can induce a reduction in resting energy expenditure even while the active cell mass (muscle mass) of the body has increased. The regulation of energy balance on a day to day basis seems to be better at high levels of energy turnover either as a consequence of the physiological need or as a consequence of the fact that athletes performing at a high level of energy expenditure have learned to ingest as much food as possible.

Body Composition↗

PubMed1991

Body composition by bioelectrical-impedance analysis compared with deuterium dilution and skinfold anthropometry in patients with chronic obstructive pulmonary disease.

Body composition is an important measure of nutritional status in patients with chronic obstructive pulmonary disease (COPD). We generated a regression model for bioelectrical impedance (BI) by using deuterium dilution (2H2O) as a reference method in 32 COPD patients, aged 63 +/- 9 y (mean +/- SD), in stable pulmonary and cardiac condition. Height squared divided by resistance (Ht2/Res) correlated well with total body water (TBW) as measured by 2H2O (r = 0.93, P less than 0.001, SEE = 1.9 L). The best-fitting regression equation to predict TBW comprised Ht2/Res and body weight (r2 = 0.89, SEE = 1.8 L, P less than 0.001). BI-predicted TBW was used to estimate BI-fat-free mass (FFM) that was compared with skinfold-thickness-based FFM predictions (Anthr-FFM). Relative to BI-FFM a significant overestimation of 4.4 +/- 0.8 kg was found by Anthr-FFM. Our results suggest that BI is a useful measure of body composition in patients with severe COPD.

Aged↗

PubMed1991

Resting energy expenditure in patients with chronic obstructive pulmonary disease.

Resting energy expenditure (REE) was measured in 68 patients with stable chronic obstructive pulmonary disease (COPD) and in 34 weight-stable, age-matched (65 +/- 8 y; means +/- SD) healthy control subjects. Fat-free mass (FFM) determined by bioelectrical resistance explained 84% of the variation in REE in the control group but only 34% in the COPD patients. REE could not reliably be predicted from regression equations either developed in healthy subjects or in COPD patients. REE adjusted for FFM was significantly higher (P less than 0.05) in weight-losing (n = 34) than in weight-stable (n = 34) patients (6851 +/- 781 and 6495 +/- 650 kJ/d, respectively). Pulmonary function was more compromised in weight-losing patients. Adjusted REE in weight-stable patients was significantly higher (P less than 0.01) than in the healthy control group (6131 +/- 405 kJ/d). In patients with COPD, factors in addition to FFM are important determinants of REE. A disease-related increase in REE develops, which may contribute to weight loss in COPD in combination with a lack of an adaptive response to undernutrition in weight-losing patients.

Aged↗